jt2ma71 said:
Hey Ron
whenI talked to ATI. You can go over the limit by intervals but if you are going to be doing 900 hp SUSTAINED then you need a bigger pulley.
I would say crank that gt42r up and get to the 800 hp sustained
OEM pulley not good for big HP :( ... sad news
- Thread starter upgradedsupra
- Start date
Hey Ron
whenI talked to ATI. You can go over the limit by intervals but if you are going to be doing 900 hp SUSTAINED then you need a bigger pulley.
I would say crank that gt42r up and get to the 800 hp sustained
IJ. said:
Ian
well stock yes but i remember that he had his custom made also and it is even larger than the OEM based 2jz damper.
suprarich said:
Rated by who? What is the OD of the belt grooves.
and if it was on my design, it is not a stocking part I can tell you that.
That's the one I've got - I'll be doing blasts to 650+rwhp, with 375 being my 'sustained' power output.
suprarich said:
ok i don't think so
the 5.5 is the stock based one. When I designed mine. The engineers specifically told me what I posted. For every 100 hp increase the OD by and inch.
My ATI that is rated at the correct 600 hp is 6.5 OD not 5.5.
but just fo giggles.. I am calling ATI.
OK just got off the phone with ATI
that is the normal OEM based one. Keep it way UNDER 600 hp and you are good.
that is the normal OEM based one. Keep it way UNDER 600 hp and you are good.
figgie said:
Figgie- Yep, I was just going by what the spec sheet on the damper says and what I was told bt ATI when I ordered them. Was told and read that they are good for 600 and under. Maybe they should stress the under part of that statement. Always good to jaw with you, remember all our debates we used to have over on I-supra.com back in the late 90's and early 2000's?
I'm still perplexed why the 7M's crank pulley is HP limited, and I'm not accepting ATI's marketing. The only load or resistance on the pulley are those from the accessories; water pump + fan, alt, power steering, etc.. That load isn't changing, nor does it increase with HP. Rather, it's constant, and the only increase experienced is overcoming the rotational inertia upon initial startup.
I'll accept that the stock rubber components may deteriorate due to age, and may become succeptible to failure, but this mode is dependent on age, service condition, and not HP. The pulley isn't spinning any faster either...
I'll await engineering data from ATI, before I accept that their pulley is "better" than the OEM's.
I'll accept that the stock rubber components may deteriorate due to age, and may become succeptible to failure, but this mode is dependent on age, service condition, and not HP. The pulley isn't spinning any faster either...
I'll await engineering data from ATI, before I accept that their pulley is "better" than the OEM's.
Its actually machining of the crank "bolt".yaitsme said:
Is sustained hp litteraly "sustained"? when they say supports -600hp sustained, thats what most hp supras(if ever) will see momentarely in the higher rpms right? and for these cars, sustained will be more like 300hp maybe?:biglaugh:, just wondering
BlackDevilSupra said:
ill agree with almost all of that...except the simple fact that the ati pulley is a good amount lighter then the oem pulley is reason enough imo to use it.
but i dont think i buy the HP rating on a crank pulley myself either. on top of that what is considered "sustained" for their hp ratings? two seconds? 10 seconds? 5 minutes?
I retract the portion about the constant nature of the load resistance (busy thinking / typing during lunch). The load on the crank does vary, it varies according to the rate of increase in RPM. However, there is a specific load on the the pulley for a (lets say) 300hp at 3000rpm, and at 6500rpm. The load curve will also be specific to 600hp or 700 or 800. Now, granted the rate of RPM increase for 600hp car will be quicker, from lets say 3000 rpm to 6500rpm, but the "amount of load" at each point, 3000 or 6500RPM, is the same regardless of engine hp, that is, the load curve is steeper for a 600hp vehicle compared to one making 300hp, but the amount of load at each point is the same - if all things remain the same, that is coolant type, alt. type, power steering type, etc...
BlackDevilSupra said: